Green by a Mile: Go Carbon Neutral on Your Next Flight

But there are also some problems:

It is a classic "pay-to-play" or even "blood money" gambit -- if you have the dough, you can buy off any damage as well as any guilt over your travel habits, which, on a global and historical scale, are pretty extravagant if you are taking transatlantic flights. It feels a bit like the practice of purchasing indulgences 500 years ago, and the practice certainly has its Martin Luther-like detractors.

Paying $6.99 to have someone plant trees still doesn't change the fact that you abetted the burning of a heap of fossil fuel and the dumping of a lot of harmful gas.

Considerable debate remains on how best to spend the funds -- wind farms or tree farms? Solar solutions or "manure into methane"? Indigenous reforestation or "tree cultures"? While tree planting is one of the most popular options for carbon offsets -- not to mention one of the easiest for average people to understand -- many experts point out that trees only sequester carbon until they die, at which point the carbon will be rereleased into the atmosphere. Other debates center around questions of whether the companies and agencies doing the work are actually delivering on their promises.

Is carbon offsetting the solution? These are early days, so it's hard to know how effective the practice will be, but doing nothing isn't much of a good option either. It's fair to assume that some of the nagging issues will start to shake out over time, but for now some folks will want to know where their money is going. Paying six bucks to take a chance on your trip resulting in a sum zero environmental impact doesn't seem like a high price to pay given the alternative -- unless you're buying property in Sacramento angling that it will be oceanfront in a few decades.

Now at a Booking Site Near You
Notwithstanding the nascent (and somewhat trendy) nature of the concept, carbon offsetting has reached the mainstream, most prominently on some of the major travel booking sites, including Expedia and Travelocity. Expedia has a partnership with TerraPass, a for-profit carbon offsetting company; Travelocity has a partnership with The Conservation Fund's Go Zero program, a nonprofit effort.

(The issue of whether a nonprofit is better than a commercial company for this type of work is also a divisive issue in the world of general do-gooding; many believe that adding a profit motive to what has typically been "charity work" is the best way to improve and sustain these efforts. On the other hand, one obvious upside of using the nonprofit is that you can deduct the expense at tax time.)

When booking a flight on Expedia, the last screen you see before confirming the purchase of your trip to Knoxville is the option to "Customize your trip to Knoxville," which includes such "Featured Activities and Services" as the Expedia Flight Protection Plan, an airport lounge pass, a subscription to a glossy travel magazine and, sure enough, the option to "Fly Green with TerraPass," one of the leading travel carbon-offsetting companies.

Based on calculations of the carbon footprint of your trip (typically measured in cubic tons, which you can calculate on the TerraPass site), Expedia and TerraPass offer three contribution levels:

Short-haul flight of 2,200 roundtrip miles at $6.99 each Cross-country flight of 6,000 roundtrip miles at $16.99 each International flight of 12,000 roundtrip miles at $28.99 each

So we've finally come to the point where taking responsibility for the impact of our travel qualifies as a "Featured Activity and Service." Call it progress!

If you prefer not to mingle your travel booking with your charitable and environmental efforts, or if you want to extend your carbon offsetting donations to other parts of your life, you can visit the Web sites of any number of competing carbon offsetting outfits to calculate your carbon consumption and make your contribution directly. See our list of carbon offset companies.

Other Ways to Offset Your Environmental Impact While Traveling
Reducing your environmental impact while traveling can be almost absurdly easy (and I'm not talking about driving without air-conditioning during summer, wearing down coats in your hotel room or other such unpleasantries):

When you leave your hotel room, turn down the heat or air-conditioning until you return, and turn off the lights.

Use the "no room service needed" option offered at many hotels. At home, you don't change your bedsheets, use a different towel, vacuum perfectly tidy rugs or scrub your sink every single day, as is the case at even the most modest hotels. If everyone in every hotel in America were to use this option, the amount of water and energy saved on washing machines alone would have an impact.

Use public transportation when traveling. In many cities riding the subway, the Underground, the El trains and the like can be a wholly satisfying way to get to know your surroundings. Folks who zip from one tourist attraction to another in a taxi learn about exactly those things: taxis and tourist attractions. It's all the actual living in between that makes a great city great.